Anastomosis generally means the surgical joining of an opening formed between vessels or organs. This includes venous and arterial anastomosis of blood vessels (both venous and arterial), bowel anastomosis (including joining of segments of the intestinal tract after partial or total colectomy), the surgical implantation of catheters, and with endoscopic surgical procedures.
Vascular anastomosis means the surgical joining by suture of two ends of a divided blood vessel following the removal of a length of vessel because of thrombosis or arteriosclerosis, or the joining of two separate vessels for revascularization purposes (bypass and free flaps).
When the blood is allowed to flow through the vessel again after suture, one problem which may arise is the seepage of blood from between the stitches, especially if antithrombotic agents have been used. phenomena which may in turn cause intravascular thrombosis by the release of thrombogenic material. In addition, haematomas favour infection.
The “Vascular Cuff Technique” in microsurgery for vascular anastomosis is used with the following objectives:
to strengthen the vascular anastomosis and prevent the vessel from twisting or kinking or becoming compressed (T. H. Robbins, “Microvascular anastomosis: vascular cuff technique”, Plastic and Reconstructive Surgery, 87, 567–568);
to achieve a haemostatic effect (N. B. Hart, British Journal of Plastic Surgery, 1987, 40, 300–304);
to reduce the number of suture stitches necessary (L. K. Hung et al., “Comparative study of artery cuff and fat wrap in microvascular anastomosis in the rat”, British Journal of Plastic Surgery, 41, 278–283); and
to create a suitable environment around the anastomosis to prevent adhesion with the surrounding tissues (T. H. Robbins, “Microvascular anastomosis: vascular cuff technique”, Plastic and Reconstructive Surgery, 87, 567–568).
Until now, surgeons have tried to solve the problem of bleeding by using biomaterials containing haemostatic agents (N. B. Hart, British Journal of Plastic Surgery, 1987, 40, 300–304). However, although these do reduce bleeding time, they also have two undesirable side effects:
poor patency of the anastomosis;
increased occurrence of perivascular fibrosis and adhesions.
Moreover, since veins are less patent than arteries, it is very dangerous to use strong haemostatic agents at a venous level because of the risk of intravascular thrombosis.
Many authors advise against the use of biomaterials because they impede the natural healing of the tissue involved in anastomosis. Instead, the use of autologous tissues consisting of a segment of blood vessel wrapped around the anastomosis is favored (Plastic and Reconstructive Surgery, Vol. 87, No. 3, March 1991, pages 567–568).
Although the use of biomaterials constituted by ester derivatives (EP0216453) and autocrosslinked hyaluronic acid derivatives (EP0341745) is already known in the prevention of post-surgical adhesions (WO97/07833), nobody has ever before observed that they possess a physical haemostatic activity that supersedes the need to use a haemostatic agent with biochemical activity on the coagulation factors which may cause intravascular thrombosis.
Another advantage of these biomaterials is their ability to prevent the vessels from adhering to the surrounding tissues and to create, surprisingly, a suitable environment to favour correct tissue regeneration, unlike other types of biomaterial used in this type of surgery.